When the Brumbies were confirmed as the Waratahs' Super Rugby semi-final opponents for Saturday night, memories of recent clashes rightly ignored the round-17 meeting in Sydney for the simple fact the visitors were missing upwards of a dozen players. If the Waratahs were looking for insights and opportunity to break the Brumbies open, looking at a game in which they did it with ease and monotonous regularity was not really going to provide the type of analysis they were seeking.

No, the round-five clash in Canberra would be a much better guide, as well as looking at the Brumbies' defensive set-ups over the past two weeks, when the Brumbies conceded only one try in the respective first halves against Western Force in round 19, and the Chiefs last week in the qualifying final.

Back in round five, the Brumbies completely shut down the Waratahs' attack - due largely to Matt Toomua and Pat McCabe rushing up on Kurtley Beale and removing any and all of his attacking space. This in turn meant no clean ball for Adam Ashley-Cooper and Israel Folau, and neither of those two players really got into the game until the final 20 minutes.

It's clear that Toomua sets the pace and the shape for the Brumbies' defence. With flanker Jarrad Butler patrolling the centre corridor and pulling down anything in his path - he's the Brumbies' leading tackler by some margin - this allows Toomua to defend wider out in the No.12 channel.

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Already this year, Toomua has pulled off some massive tackles with midfielders Super Rugby-wide not knowing their fate until they feel the impact and look up to see the Brumbies fly-half all over them. In turn, this has led to the belief that Beale might be able to take advantage of the space in behind Toomua through the use of his short kicking game; and that tactic could well work if the opportunity is there both in regular attack, and on kick-returns. But only if the opportunity is really there.

The Chiefs thought they had an opportunity last Saturday night, but they quickly learned the lesson that apparent space in the Brumbies defence is not the same as actual space.

It all started from a defensive lineout in the Brumbies' 22. Nic White launched a box kick from behind the clean lineout, and Chiefs winger James Lowe regathered back behind his own 40m line and headed infield to link with Dwayne Sweeney. The fullback ran beyond the 40m line and, looking up, would have noticed Brumbies forwards coming across in cover with his counterpart, Jesse Mogg, set deep, expecting the Chiefs to clear out of their own half and ensuring he was in position to kick long from inside his own 22.

As Sweeney chipped, he drew an attempted charge-down from Scott Fardy. The image above shows both Christian Leali'ifano (obscured) and Tevita Kuridrani have come up quickly, too, probably adding to Sweeney's belief of space in behind. Brumbies forwards Sam Carter and Ben Mowen were also coming across to join the front line from the near side. Note also in the image that Chiefs inside centre Bundee Aki (to Sweeney's right) is flat-footed and not really a support option. Just out of this shot to Aki's left, Aaron Cruden was actually heading back toward his own try line to field a return kick. It's clear neither expected Sweeney to chip ahead.

What Sweeney didn't see when he chipped through was White coming back across field from the position of the original lineout. He's dropped straight into that very typical "sweeper" position that he occupies in defence, and got to the ball on the full. Excuse my rough mudmap skills, but the overhead would have looked something like this as Sweeney kicked through:

White timed his pass to Mogg beautifully, and the fullback burnt Aki on the outside with ease. Robbie Coleman's inside run from behind started around about now, too, and he was on Mogg's inside to scoot away as the fullback came back inside to engage Cruden in cover.

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This is something Beale will need to be mindful of, if he believes the chip kick is the way to get in behind the Brumbies' rush defence. White is very rarely in the front line - he openly admits to making fewer tackles in a season than some of his forwards makes in a match - so he plays that sweeper role very well; his speed off the mark allows him to get where he needs to be very quickly, too.

The chip kick may seem to be on for Beale, but he'll need to be aware that space in behind the Brumbies defence is often an illusion.